This invention relates to an improved body-contacting surface or topsheet for absorbent articles, bandages, or other such devices, and more particularly to a topsheet that is comfortable when it is placed in contact with hydrous body tissues. The present invention also relates to absorbent devices such as sanitary napkins, tampons, pantiliners, interlabial devices, incontinence devices, and bandages, which have such a topsheet. An improved absorbent structure for an absorbent article is also disclosed. The present invention further relates to a method of capturing discharges from a source of discharges on a wearer""s body in which at least a portion of the source of discharges is located within hydrous membranes having irregular surfaces (e.g., a female wearer""s interlabial or intervaginal space).
All manner and variety of absorbent articles configured for the absorption of body fluids such as menses, urine and feces are well known. With respect to feminine protection devices, the art has offered two basic types; sanitary napkins have been developed for external wear about the pudendal region while tampons have been developed for internal wear within the vaginal cavity for interruption of menstrual flow therefrom. Such tampon devices are disclosed in U.S. Pat. No. 4,412,833, entitled xe2x80x9cTampon Applicatorxe2x80x9d, issued to Weigner, et al. on Nov. 1, 1983, and U.S. Pat. No. 4,413,986, entitled xe2x80x9cTampon Assembly With Means For Sterile Insertionxe2x80x9d, issued to Jacobs on Nov. 8, 1983.
Hybrid devices which attempt to merge the structural features of the sanitary napkins and the tampons into a single device have also been proposed. Such hybrid devices are disclosed in U.S. Pat. No. 2,092,346, entitled xe2x80x9cCatamenial Padxe2x80x9d, issued to Arone on Sep. 7, 1937, and U.S. Pat. No. 3,905,372, entitled xe2x80x9cFeminine Hygiene Protective Shieldxe2x80x9d, issued to Denkinger on Sep. 16, 1975. Other less intrusive hybrid devices are known as labial or interlabial sanitary napkins and are characterized by having a portion which at least partially resides within the wearer""s vestibule and a portion which at least partially resides external of the wearer""s vestibule. Such devices are disclosed in U.S. Pat. No. 2,662,527, entitled xe2x80x9cSanitary Padxe2x80x9d, issued to Jacks on Dec. 15, 1953; U.S. Pat. No. 4,631,062, entitled xe2x80x9cLabial Sanitary Padxe2x80x9d, issued to Lassen, et al. on Dec. 23, 1986; and U.S. Pat. No. 4,673,403, entitled xe2x80x9cMethod and Pad Allowing Improved Placement of Catamenial Devicesxe2x80x9d, issued to Lassen, et al. on Jun. 16, 1987.
Interlabial pads have the potential to provide even greater freedom from inconvenience because of their small size and reduced risk of leakage. Numerous attempts have been made in the past to produce absorbent devices which would combine the best features of tampons and sanitary napkins while avoiding at least some of the disadvantages associated with each of these types of devices. Examples of such devices are described in U.S. Pat. No. 2,917,049 issued to Delaney on Dec. 15, 1959, U.S. Pat. No. 3,420,235 issued to Harmon on Jan. 7, 1969, U.S. Pat. No. 4,595,392 issued to Johnson, et al. on Jun. 17, 1986, and U.S. Pat. No. 5,484,429 issued to Vukos, et al. on Jan. 16, 1996. A commercially available interlabial device is the INSYNC Miniform interlabial pad which is marketed by A-Fem of Portland, Oreg. and described in U.S. Pat. Nos. 3,983,873 and 4,175,561 issued to Hirschman on Oct. 5, 1976 and Nov. 27, 1979, respectively.
Many of these devices have not met with great commercial success, however. There are drawbacks associated with all of the above products. For example, the device described in the Delaney patent does not appear to be capable of an easy and comfortable insertion, due to the possibility of the layers of absorbent material opening up during insertion. The commercially available IN-SYNC interlabial device suffers from the disadvantage that it may tend to allow by-pass flow around its edges. Such flow can cause body soiling or panty soiling which many consumers find unacceptable.
Improved interlabial devices are described in the following patents assigned to The Procter and Gamble Company: U.S. Pat. Nos. 5,762,644; 5,885,265; 5,891,126; 5,895,381; 5,916,205; 5,928,452; 5,951,537; 5,968,026; 6,033,391; and, 6,045,544. The search for improved interlabial devices has, however, continued. In particular, there is a need for improved, more comfortable, topsheets for such devices that contact the wearer""s inner labia majora surfaces, and the skin within the vaginal vault.
Products that are to be worn predominantly interlabially are expected to remain in place without any of the usual panty attachment approaches (i.e., adhesives). In order for such products to remain positioned within the labia they are required to adapt to the labial vault and remain fixed via a combination of structural adaptation (i.e. fit) and physical interactions such as friction (i.e. slippage control) or adhesion due to capillary suction.
Products that are worn interlabially are predominantly worn within the labial vault and enclosed by the labia minora and the labia majora. Anatomically speaking, there are striking differences in both physical structure and the properties of the skin within the labia, particularly the labia minora compared to adjacent skin surfaces such as in the perineal groove, buttocks and inner thigh regions that would normally be contacted by a sanitary napkin. It is important to differentiate between external surfaces (such as the buttocks, perineal grove, the outwardly facing labia majora surfaces) and internal surfaces (such as the labia minora, vulva vault, and the vagina). As one progresses from the xe2x80x9cexternalxe2x80x9d bodily surfaces of the buttocks or inner thighs, representative of a normal stratum cornea, towards the vulva the stratum cornea begins to change. The vulva majora (externally facing surfaces) still exhibits a stratum cornea but somewhat thickened and in a somewhat immune sensitized state indicative of a greater sensitivity to external influence. Nevertheless, such xe2x80x9cexternalxe2x80x9d skin types, macroscopically viewed, are still considered to be relatively smooth and dry to the touch. They are considered to be relatively hydrophobic in nature. They exhibit similar degrees of hydration to other bodily sites, similar friction coefficients (especially when absorbent materials are next to these tissues) and degrees of elasticity and compressibility that are all within a factor of three (see Elsner et al., British Journal of Dermatology (1990). Issue 122, p 607-614, and Elsner et al., Dermatologica (1990). Issue 181, p 88-91). Moving interlabially from the labia majora (moving to the internal bodily surfaces) to the labia minora and then internally (vaginal vault) a fundamental change in the properties of the skin or labial membrane occurs. The inner labial minora surfaces are starting to become more characteristic of a mucosa membrane than a stratum cornea. As one moves from the labial vault into the vaginal vault the transition is complete to a mucosa membrane. Tissues within the labial vault, especially the inward facing surfaces of the labia minora are permanently wet, are believed to have a significantly higher friction coefficient, elasticity, and compressibility. These membranes are highly textured (irregular surface) and are hydrophilic not hydrophobic.
Traditionally, on externally worn absorbent articles (contacting predominantly xe2x80x9cexternalxe2x80x9d bodily surfaces) such as sanitary napkins, a hydrophilic topsheet or hydrophobic topsheets treated to be hydrophilic (such as with a surfactant) have been utilized to ensure adequate absorption and transmission of bodily discharges to the absorbent core structure. There has been a significant number of disclosures on approaches to create soft, performing topsheets for use externally and in contact with dry and relatively smooth skin surfaces such as in the perineal groove, buttocks and inner thigh regions.
In the case of internally worn disposable absorbent products (contacting predominantly xe2x80x9cinternalxe2x80x9d bodily surfaces, traditionally absorbent and hydrophilic topsheets and particularly rayon based topsheets (delivering biodegradability and softness) have been chosen such that the products can be disposed of by flushing down a toilet. Such topsheets (particularly rayon webs) have also been utilized for hybrid absorbent products that are either partially or wholly worn within the labial vault. However, the applicants have discovered that traditional hydrophilic and particularly absorbent hydrophilic topsheets are not ideally suited for internal and particularly interlabially worn absorbent products, and in fact may contribute significantly to discomfort and perceptions of soreness and irritation while wearing such products in use. This seems to be contrary to the known art that would expect soft, smooth, hydrophilic topsheets such as rayon or many nonwovens to be ideal candidates for a general feminine absorbent article.
This conflict with prior art can perhaps be understood if we consider an interlabially worn absorbent pad with an absorbent, hydrophilic topsheet such as a rayon web. On placing such a product within the labia and specifically in contact with the xe2x80x9cinternalxe2x80x9d facing surfaces of the labial minora, such topsheets are able to absorb labial secretions. Apart from tending to dry the labial membrane (one source of discomfort and irritation) the topsheet has a natural tendency to adhere to the labial membrane via hydrophilic-hydrophilic compatibility. This establishes yet another source of discomfort as the labial membrane is very elastic and is expected to deform/freely move with bodily motion and with respect to each other. If an absorbent product is attaching to this membrane and is unable to move to the same degree of elasticity, a process of adhere-sheer is set up during bodily motion that creates a level of discomfort (rough, dry rubbing sensations) for the products user.
Several approaches have been attempted to provide improved, more comfortable topsheets for such products. European Patent Application 0 685 215 A1 is directed to a xe2x80x9cVaginal moisture balanced tampon and process.xe2x80x9d This publication is directed toward reducing vaginal epithelium drying by reducing the capillary suction pressure of a tampon in early use. This is said to be accomplished by modifying the capillary suction pressure of the surface of the tampon by using hydrophobic components in the tampon, such as hydrophobic fibers and/or a hydrophobic cover material. Other means of obtaining a lower capillary suction pressure are said to include increasing the denier of the fibers in the tampon""s absorbent core and/or decreasing the density of the tampon.
U.S. Pat. No. 4,846,824, Lassen, et al., entitled xe2x80x9cLabial Sanitary Padxe2x80x9d describes another approach. The Lassen ""824 patent indicates that the use of a physiologically hydrous cover maintains the ideal level of moisture within the urogenital region. The term xe2x80x9cphysiologically hydrousxe2x80x9d is said to connote a cover material that maintains a suitably moist interface between the tissues of the vestibule and the pad when disposed in the vestibular environment. An example of a highly preferred cover in the Lassen ""824 patent is one made from a spunlaced polyester such as that sold under the tradename xe2x80x9cSONTARAxe2x80x9d by E. I. DuPont Company.
Therefore, a need exists for improved devices which are worn adjacent to a wearer""s hydrous body tissues, such interlabial device which will reduce the incidence of body and panty soiling when used. In particular, a need exists for improved, more comfortable, topsheets for such devices that contact the wearer""s inner labia majora surfaces, and the skin within the vaginal vault. Such a device should be easy to insert and be comfortable during wear. Preferably, such a device will be comfortable enough for everyday use, if desired. A need also exists for an improved interlabial device which has sufficient capacity to serve as a stand alone product during the heavy flow days of a wearer""s menstrual period, and is not subject to the problem of falling out of the interlabial space when loaded to its absorbent capacity. A need also exists for other types of absorbent devices such as sanitary napkins, tampons, pantiliners, interlabial devices, incontinence devices, and bandages, which have such a topsheet.
The present invention relates to an improved body-contacting surface or topsheet for absorbent devices that come into contact with a wearer""s hydrous body tissues. These hydrous body tissues may include, but are not limited to hydrous tissues such as interlabial skin or tissue and mucosal tissues such as vaginal tissues. In one non-limiting embodiment, the topsheet comprises a non-absorbent, moderately hydrophilic to substantially hydrophobic nonwoven web. The topsheet can have a critical surface tension of less than or equal to about 45 dynes/cm, preferably less than or equal to about 40 dynes/cm. In one embodiment, the nonwoven web has been mechanically modified so that it is extensible in at least one direction in an amount greater than or equal to about 30% under a force of 50 grams. The topsheet preferably undergoes a caliper change of greater than or equal to about 30% under a pressure of 1,000 Pa after being subjected to a pressure of 250 Pa. The topsheet is placed on absorbent devices such as sanitary napkins, tampons, pantiliners, interlabial devices, incontinence devices, bandages, and other articles.
The present invention also relates to absorbent devices such as sanitary napkins, tampons, pantiliners, interlabial devices, incontinence devices, bandages, and other articles which have such an improved topsheet. The term xe2x80x9cinterlabial devicexe2x80x9d refers to an absorbent device that is at least partially insertable into the interlabial space of a female wearer for catamenial purposes (including menses and mid-cycle discharges), incontinence protection (including urine), or both.
The present invention further relates to a method of capturing discharges from a source of discharges on a wearer""s body in which at least a portion of the source of discharges is located within hydrous membranes having irregular surfaces (e.g., a female wearer""s interlabial or intervaginal space). The method comprises: providing an absorbent article having a liquid pervious top surface structure, said top surface structure having a body contacting surface, wherein said top surface structure has at least regions that are extensible; and placing the absorbent article adjacent to the hydrous membranes of a wearer""s body, with the body-contacting surface of the top surface structure at least partially in contact with the hydrous membranes.
The absorbent device utilizing the topsheet can be of any suitable structure known in the art, or it may be of a novel structure. The absorbent interlabial device, in one non-limiting embodiment, is a small pad-like structure that comprises a liquid pervious topsheet, a liquid impervious backsheet which is joined to the topsheet, and an absorbent core positioned between the topsheet and backsheet. The device preferably comprises an axis of preferred bending, preferably located generally along the longitudinal centerline of the device. When the device is folded along this axis and inserted into the wearer""s interlabial space, the topsheet maintains contact with the walls of the wearer""s labia. Preferably, the device comprises biodegradable materials. In some embodiments, the backsheet of the absorbent interlabial device is water dispersible. In other embodiments, the backsheet can be eliminated. The backsheet can be eliminated if the underside of the absorbent core is coated. Alternatively, the backsheet can be eliminated if the device is primarily contained within the labia, and the interlabial device is folded along a longitudinal axis. In such a case, the device assumes an inverted V or U-shaped cross-sectional structure, and the portions of the device which would normally be provided with a backsheet will face inward toward each other, and will not contact a wearer""s garments. The elimination of a backsheet will improve the breathability of the device. A tab may be joined to the underside of the device to facilitate insertion and optional removal of the device with the fingers.